delayed autoresponder w/ loop protection script

I'm looking for a PHP-based autoresponder/vacation response script (ideally under GPL license) with the following requirements:

- subscription by email
- delayed first response. Most autoresponder sends out first response immediately after subscription
- schedule follow-up messages by sequential time (ie. 2 hours after subscription) or absolute time (ie. Monday @ 5pm, Tuesday @ 8am)
- loop protection... so that if the same subscriber subscribes again, the script will only take that same user through the follow-up sequence once.

I'm wiling to pay a finder's fee or pay someone to do this custom script.

Thanks!
Steve

 

I second that. Any luck Steve?

 

no luck yet, so i'm building my own. will keep you posted.